Golf club heads come in many different forms and makes, such as wood- or metalwood-type (including drivers and fairway woods), iron-type (including wedge-type club heads), utility- or specialty-type, and putter-type club heads. Each of these types has a prescribed function and make-up. The present invention primarily relates to hollow golf club heads, which may be any of those types, but are primarily wood-type and utility-type golf club heads.
The design and manufacture of wood-type golf clubs requires careful attention to club head construction. Among the many factors that must be considered are material selection, material treatment, structural integrity, and overall geometric design. Exemplary geometric design considerations include loft, lie, face angle, horizontal face bulge, vertical face roll, face size, sole curvature, center of gravity, moment of inertia, and overall head weight. The interior design of the club head may be tailored to achieve particular characteristics, such as by including a hosel or other shaft attachment means, perimeter weighting on the face or body of the club head, and fillers within hollow club heads. Club heads typically are formed from stainless steel, aluminum, or titanium, and are cast, stamped as by forming sheet metal with pressure, forged, or formed by a combination of any two or more of these processes. Some club heads are formed from multiple pieces that are welded, bonded or otherwise joined together to form a hollow head. The multi-piece constructions facilitate access to the cavity formed within the club head, thereby permitting the attachment of various other components to the head such as internal weights and the club shaft. The cavity may remain empty, or may be partially or completely filled, such as with foam. An adhesive may be injected into the club head to provide the correct swing weight and to collect and retain any debris that may be in the club head. In addition, due to difficulties in manufacturing one-piece club heads to high dimensional tolerances, the use of multi-piece constructions allows the manufacture of a club head to a tight set of standards.
With golfers constantly searching for golf clubs that provide greater distance, particularly drivers, the golf industry has responded by providing golf clubs specifically designed with distance in mind. The head sizes of wood-type golf clubs have increased, which has allowed improved mass manipulation. The manipulation of mass allows the designer to alter attributes, such as the moment of inertia and the location of the center of gravity to provide a more forgiving golf club. In particular, providing a higher moment of inertia increases the ability of the golf club head to resist twisting on imperfect golf ball impacts. Additionally, the size of the golf club head allows more discretion in locating the center of gravity.
It is desirable to provide a golf club that provides for increased discretionary mass while providing desired performance and sound attributes.